Microsoft's Windows Mobile 6 Operating System - aka "Crossbow" - is slated to officially launch next week at the 3GSM World Congress in Barcelona.  The new OS will come in three flavors, Standard, Classic (for Pocket PC), and Professional.  Check out engadgetmobile.com for some screenshots.

Now a report has leaked stating that T-Mobile will be carrying new Windows Mobile 6 Devices beginning in the second quarter of this year.  While no details about possible upgrades for existing Windows Mobile 5 devices were given beyond "it's up to the operator," a product manager for Microsoft was reported as stating that T-Mobile will be the first US carrier to launch Crossbow-equipped phones.

As reported earlier, Crossbow will feature a madeover look and feel along with numerous "under the hood" improvements including HTML email support.